Drinking Water Quality: Physical and Chemical Evaluation of Tap and Packaged Waters from Eight Local Government Areas in Lagos, Nigeria

Abstract

Introduction The inadequacy of pipe borne water supplies in urban centers is a growing problem. In recent years, packaged waters became major sources of drinking water in the households and at work. Aim This study aimed at evaluates the physical and chemical quality of packaged water sold in some part of Lagos Metropolis. Compare the quality with that of tap water; and check compliance with respect to national and international regulatory standards. Materials and Methods Thirty tap water and fifty seven packaged water samples of different types were selected by random sampling and analysed for trace metals using atomic absorption spectrometry; Total hardness was measured titrimetically; pH, electrical conductivity and anions were measured using meters. Results and Conclusion The results showed that the concentrations of trace metals and anions in both tap and packaged waters were below the drinking water threshold values stipulated by national and international agencies, with the exception of the nitrate (NO3-), where 11 % and 20 % respectively of the bottled and sachet water samples investigated exceeded the USEPA standard of 10 mg L-1. This finding may result from the geological formations through which the ground water flows and substances dissolving from either natural sources or from household plumbing systems. This study concludes that the systematic monitoring by drinking water authorities of water quality is essential and the enforcement agencies in the state (NAFDAC and the Ministry of Health) need to get the producers of 'packaged water' to comply with the national drinking water guidelines.